LIFE ON EARTH: 3.2 BILLION YEARS AGO:

Beer w/Straw said:
Well, have we found life on other planets and compare what elements are needed?
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We are many years away from even traveling to planets with the right gravity and chemistry that might support life. And considering how long the voyage would be and how long it will even take the radio waves they send back to reach Earth, it's very unlikely that even the youngest among us will be around to learn about what they discovered.
 
Fraggle Rocker said:
We are many years away from even traveling to planets with the right gravity and chemistry that might support life. And considering how long the voyage would be and how long it will even take the radio waves they send back to reach Earth, it's very unlikely that even the youngest among us will be around to learn about what they discovered.
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Speaking interstellar of course.
With some luck, the right political outlook and good economic times, we could do it in a couple of decades, to Mars at least.
I think I may just see that out!
 
paddoboy said:
Speaking interstellar of course. With some luck, the right political outlook and good economic times, we could do it in a couple of decades, to Mars at least. I think I may just see that out!
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We've already explored enough of Mars to be fairly certain that it does not support life, although it may have done so a couple of billion years ago when it was warmer and wetter. Perhaps a few ancient lifeforms were just barely able to adapt to the slow transition to today's barren, virtually airless conditions.

Of course, the problem that nobody talks about when enthusiastically hoping to find life on another planet: It might be so different from life on Earth, perhaps not even carbon-based, that we won't even recognize it when we see it.

It's human hubris to assume that life everywhere in the universe has the same general properties as life on Earth.
 
Fraggle Rocker said:
We've already explored enough of Mars to be fairly certain that it does not support life, although it may have done so a couple of billion years ago when it was warmer and wetter. Perhaps a few ancient lifeforms were just barely able to adapt to the slow transition to today's barren, virtually airless conditions.
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Most likely correct, but just perhaps, we just have not dug deep enough as yet.
Fraggle Rocker said:
Of course, the problem that nobody talks about when enthusiastically hoping to find life on another planet: It might be so different from life on Earth, perhaps not even carbon-based, that we won't even recognize it when we see it.
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Can't really argue with that.

Fraggle Rocker said:
It's human hubris to assume that life everywhere in the universe has the same general properties as life on Earth.
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Agreed.
I envisage life throughout the Universe, to be at many scales of evolutionary advancement, including levels of intelligence comparable with our own and even in advance of that, separated only by the tyranny of time and distance.

I sincerely hope that Seth Shostak's prediction of finding evidence for life within the next 20 years is realized....Well at least before I kick the bucket!
 
paddoboy said:
I sincerely hope that Seth Shostak's prediction of finding evidence for life within the next 20 years is realized....Well at least before I kick the bucket!
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With today's technology, we cannot possibly land a probe (or put it orbit) on one of the exoplanets that have been identified as reasonable places to hope for life (gravity, temperature, elements, atmosphere, rotation rate, polar angle, orbital stability, etc.) within a mere 20 years.

Kepler 22-B is the closest planet in its sun's habitable zone that we have found. And it is six hundred light years away! So it will take at least 600 years to get there. And, of course, another 600 years for the probe to send back the message telling us that it found a civilization with post-industrial technology.

So you and I will probably not be around to hear the joyful news. :(
 
paddoboy said:
I am sure Seth was inferring detection of electromagnetic signals of sorts being detected, and/or some form of primitive life within our own solar system.
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Very unlikely. In an enormous universe with more than one quintillion stars, it's reasonable to expect that our star is not the only one with a life-bearing planet.

But if you're just looking at our solar system, the probability of life on Mars or Venus is extremely low, and on the other planets we might as well round the probability figure to zero.

Life is a local reversal of entropy, so the places to look for it are where the environment could reasonably support a local reversal of entropy.
 
Fraggle Rocker said:
In an enormous universe with more than one quintillion stars, it's reasonable to expect that our star is not the only one with a life-bearing planet.
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With the additional fact of the ingredients for life being everywhere we look, I would totally agree with that sentiment.
Certainly a logical assumption to make.

Fraggle Rocker said:
But if you're just looking at our solar system, the probability of life on Mars or Venus is extremely low, and on the other planets we might as well round the probability figure to zero.
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I agree in actual fact. We have far better chances of detecting life within our solar system, on some of the moons, like Europa and Enceledus.
 
paddoboy said:
I agree in actual fact. We have far better chances of detecting life within our solar system, on some of the moons, like Europa and Enceledus.
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That's a long shot. Too cold, and in most cases, not enough gravity.

If life has actually sprung up on one of those satellites, it would likely not be anything at all like Earth life. The odds are good that humans who eventually land there would not even recognize it as alive.

For starters, whatever it is wouldn't be moving fast enough to catch anybody's eye. ;)
 
Fraggle Rocker said:
That's a long shot. Too cold, and in most cases, not enough gravity.

If life has actually sprung up on one of those satellites, it would likely not be anything at all like Earth life. The odds are good that humans who eventually land there would not even recognize it as alive.

For starters, whatever it is wouldn't be moving fast enough to catch anybody's eye. ;)
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To be fair - geothermal vents. It might be more recognizable than you're expecting...
 
Fraggle Rocker said:
That's a long shot. Too cold, and in most cases, not enough gravity.

If life has actually sprung up on one of those satellites, it would likely not be anything at all like Earth life. The odds are good that humans who eventually land there would not even recognize it as alive.

For starters, whatever it is wouldn't be moving fast enough to catch anybody's eye. ;)
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I think based on our criteria for being alive we won't have problem recognizing what's alive. Especially if it's trying to eat us. Some analysis may be required but we'll figure that part out.
 
Fraggle Rocker said:
That's a long shot. Too cold, and in most cases, not enough gravity.

If life has actually sprung up on one of those satellites, it would likely not be anything at all like Earth life. The odds are good that humans who eventually land there would not even recognize it as alive.

For starters, whatever it is wouldn't be moving fast enough to catch anybody's eye. ;)
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Europa Gravity is ~ .1345_earth gravity. Kinda like Barsoom but with way more lift potential.
 
brucep said:
I think based on our criteria for being alive we won't have problem recognizing what's alive. Especially if it's trying to eat us.
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The chemistry of an organism in such an exceptionally different environment is likely to be so different from ours that it wouldn't be able to eat one of us any more than vice versa.

Not to mention, our "criteria for being alive" are based entirely on our observations of terrestrial life. Homeostasis and cellular structure, in particular, don't seem like deal-breakers, yet they are probably the two criteria that would be most visible, and therefore the ones we'd be most likely to look for.
 
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